The present invention relates to a palletizing apparatus for stacking horizontal rows of packages such as packing cases, boxes or the like on a pallet.
Many prior art palletizers are of the type which form a single line of packages at a time as they come out of an input conveyor. These single rows of packages may be formed on a set of rollers and the individual rows of packages so formed may be transversely scraped from the set of rollers before being pushed onto a pallet in a stacking section.
The prior art palletizers which form a single line of packages in this way have the drawback that they are relatively slow in operation and have a low capacity for stacking packages. Indeed, the formation of a single row of packages on a set of rollers makes it necessary to stop the input conveyor and to interrupt the operation of the palletizer each time a row is completed, especially when the row is to be scraped off transversely. In addition, in the instance of stacking packages, certain of which are aligned at right angles with respect to the others, these prior art palletizers require the use of a suitable bevel gear which constitutes, not only an onerous additional device, but also causes a slowing down of the operation of the palletizing apparatus.
The object of the invention is new palletizing apparatus capable of forming several parallel rows of packages so as to have a substantially greater capacity for stacking packages than the prior art without consuming more power.
In a preferred embodiment of the invention, the palletizing apparatus stacks successive horizontal rows of packages such as packing cases, boxes and the like. The input section includes an input conveyor successively conveying packages. A row forming section includes rollers or other conveyor means communicating with the input conveyor for forming rows of packages received from the input conveyor. First bar means extend transversely across the row forming section for stopping the conveyance of the rows on the rollers while also pushing and discharging the rows formed on the rollers into the stacking section of the apparatus.
In accordance with this invention, a retractable distributing device moves laterally over the surface of the rollers so as to selectively push packages laterally with respect to the path of those packages leaving the input conveyor thereby forming a plurality of rows on the rollers of the input section. The rows so formed may then be moved forward by the transversely extending bar means into the stacking section. The retractable distributing device may comprise a horizontal bar which extends longitudinally along the path of the articles leaving the input conveyor and above the rollers. The bar may be supported by at least one support member which extends upwardly between a pair of rollers and is actuated in response to motor drive means.
In accordance with another important aspect of the invention, at least one retractable turning device is provided in the input section for turning packages at right angles. This device may comprise a bar or member which extends vertically between a pair of rollers and engages a package near or at a corner as the package moves along the rollers toward the transversely extending bar. Retraction of the turning device is accomplished by motor means located beneath the rollers as, for example, a hydraulic jack.
In order to permit the input section to function substantially independently of the movement of the pallet on the elevator in the stacking section, the stacking section includes a fixed support plate in communication with the rollers and a movable support plate which may be displaced horizontally from a position beneath the fixed support plate to a position above the pallet. At least one second transverse bar means is provided for moving packages on the fixed support plate onto the movable support plate. The second transverse bar means has a dual function of pushing the rows of packages from the fixed support plate onto the movable support plate when the movable support plate is in the forward position while also scraping the packages from the movable support plate when the movable support plate is retracted to a position beneath the fixed support plate.
The first transverse bar means and the second transverse bar means may each comprise a pair of transversely extending bars which are mounted on endless chains. The endless chains of the first transversely extending bars of the input section may be disposed both above and below the rollers so as to locate one of the first transverse bars in contact with the packages at the front of the row forming section and the other of the first transverse bars below the rollers and behind the rows so as to permit the one transverse bar above the rollers to stop the packages while the other transverse bar below the rollers may be used to push or scrape the rows of packages off the rollers and onto the fixed support plate in the stacking section when the chains supporting the first transverse bars are advanced,. The chains supporting the second transverse bars are located above the fixed support plate with one transverse bar being located in a position at the rear of the fixed support plate and above the path of the packages as they are moved onto the fixed support plate with the other of the second transverse bars being located at the front of the fixed support plate and in the path of the packages as they are moved from the rollers onto the fixed support plate. After the movable support plate has been moved to a position forward of the fixed support plate and above the pallet, the chains supporting the second transverse bars are moved so as to bring the bar at the rear of the fixed support plate into contact with the packages on the plate while moving the bar at the front of the plate out of the path of the packages thereby permitting the packages to move onto the movable support plate.
In accordance with another object of this invention, the palletizing apparatus may be automated by the use of a photoelectric cell which is actuated by the packages emerging from the input conveyor. Pulses from the photoelectric cell are applied to a programmed control means which is utilized to control the position of the distributor and return devices as well as the movement of the rollers, movement of the transverse bars, and movement of the pallet elevator.
Other details and particulars of this invention will appear from the description of the accompanying drawings which illustrate the embodiment of the invention in a schematic and purely exemplary way.